The logical flaw in their argument also doesn't depend on the EPA's actions! In fact, the additional color you added works against the claim, in their logic.

Strictly speaking, you're right: they're more than prepared to disregard the position of the EPA (all of us seem willing to). But said designation being currently under review is pertinent to the possibility they raise, namely that consensus has changed in the past, and sometimes the more skeptical or conservative heading taken preemptively has been borne out wise.